CodY of Streptococcus pneumoniae:: Link between nutritional gene regulation and colonization
CodY of Streptococcus pneumoniae:: Link between nutritional gene regulation and colonization
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DOI：
10.1128/jb.00917-07
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发表时间：
2008-01-01
影响因子：
3.2
通讯作者：
Hermans, Peter W. M.
中科院分区：
文献类型：
--
作者：
Hendriksen, Wouter T.;Bootsma, Hester J.;Hermans, Peter W. M.
CodY是一种主要参与氨基酸代谢的营养调节剂。它已在枯草芽孢杆菌和乳酸乳球菌中得到广泛研究。我们研究了CodY在人类病原体肺炎链球菌的基因调控和毒力中的作用。我们构建了一个codY突变体，并通过基因芯片和双向差异凝胶电泳分析检测基因和蛋白表达的影响。肺炎球菌CodY调节子主要由参与氨基酸代谢的基因组成，但也包括其他几个细胞过程，如碳代谢和铁摄取。通过电泳迁移率变动分析和DNA足迹法，我们发现，大多数的目标确定的CodY的直接控制下。通过突变预测代表CodY盒的DNA，乳酸菌共有序列，我们证明了该序列确实是体外DNA结合靶启动子所必需的。类似于L。乳酸菌，DNA结合的CodY增强支链氨基酸的存在下，但不是由GTP。我们在实验小鼠模型中观察到codY在小鼠鼻咽和肺中转录，并且是定植所特别需要的。这一发现通过codY突变体在体外粘附于鼻咽细胞的能力减弱而得到强调。此外，我们发现，由CodY激活的pcpA是粘附鼻咽细胞所必需的，这表明营养调节和粘附之间存在直接联系。总之，肺炎球菌CodY主要调节参与氨基酸代谢的基因，并有助于感染的早期阶段，即，鼻咽的定植。
CodY is a nutritional regulator mainly involved in amino acid metabolism. It has been extensively studied in Bacillus subtilis and Lactococcus lactis. We investigated the role of CodY in gene regulation and virulence of the human pathogen Streptococcus pneumoniae. We constructed a codY mutant and examined the effect on gene and protein expression by microarray and two-dimensional differential gel electrophoresis analysis. The pneumococcal CodY regulon was found to consist predominantly of genes involved in amino acid metabolism but also several other cellular processes, such as carbon metabolism and iron uptake. By means of electrophoretic mobility shift assays and DNA footprinting, we showed that most of the targets identified are under the direct control of CodY. By mutating DNA predicted to represent the CodY box based on the L. lactis consensus, we demonstrated that this sequence is indeed required for in vitro DNA binding to target promoters. Similar to L. lactis, DNA binding of CodY was enhanced in the presence of branched-chain amino acids, but not by GTP. We observed in experimental mouse models that codY is transcribed in the murine nasopharynx and lungs and is specifically required for colonization. This finding was underscored by the diminished ability of the codY mutant to adhere to nasopharyngeal cells in vitro. Furthermore, we found that pcpA, activated by CodY, is required for adherence to nasopharyngeal cells, suggesting a direct link between nutritional regulation and adherence. In conclusion, pneumococcal CodY predominantly regulates genes involved in amino acid metabolism and contributes to the early stages of infection, i.e., colonization of the nasopharynx.